Lecture 3: Carrier Ethernet Technology · Ethernet priority 802.1p is amendment in 802.1q Allow...

Lic.(Tech.) Marko Luoma (1/49)‏

S-38.3191 Verkkopalvelujen tuotanto

S-38.3191 Network Service Provisioning

Lecture 3: Carrier Ethernet Technology


Ethernet Two frame types:

Ethernet-II: Address fiels are followed by lenght field

IEEE-802.3: Address fields are followed by type field

Multiprotocol capability» VLAN is a ’protocol’

Frame sizes 64 <-> 1518 Bytes Historically due to collision detection in large flat networks Additionally

IFG: 12bytes Preamble: bytes Start delimeter: 1 byte

DataStart(1 byte)‏

DST Add(6 bytes)‏

PADPreamble(7 bytes)‏

FCS(4 bytes)‏

SRC Add(6 bytes)‏

Length(2 bytes)‏


Virtualisation of Ethernet Virtual LAN is a network within the network

It logically creates virtual networks on top of physical network

Virtuality is realized with additional fields in the frame

Tag Protocol ID: 0x8100 for 802.1q

Priority: 802.1p priority

CFI: Canonical format indicator (MAC address can be or not)‏

VLAN ID: 4096 VLAN IDs

» Only few (read expensive) devices support simultaneously this number

DataStart(1 byte)‏

DST Add(6 bytes)‏

PADPreamble(7 bytes)‏

FCS(4 bytes)‏

SRC Add(6 bytes)‏

Length(2 bytes)‏

Priority(3 bits)‏

CFI(1 bit)‏

(0x8100)‏(2 bytes)‏

VLAN ID(12 bits)‏


VLAN Separation of network resources to logical units is based on forwarding

databases (FDB)‏

In independent mode, each VLAN has its own FDB

Clients residing in different forwarding table are not able to communicate without external help

In shared mode, part of VLANs share a common FDB

Clients residing (symmetrically) in same FDB are able to communicate together

Communication between VLANs is established with

‘Misconfigured’ bridge that connects VLANs together

Router forwarding packets between VLANs


VLANs PVID ~ Port VLAN identifier

Each and every switchport is assigned to belong to particular VLAN

Incoming untagged traffic is forwarded by using this VLANs FDB

Address learning is bound to that FDB

Incoming tagged traffic is associated to VLAN based on VID or FDB depending on ingress filtering rules

VID ~ VLAN identifier

If frame is

Coming in from a trunk interface it contains 802.1q tag which carries VID

Going out to trunk link packet is coded to 802.1q tag mode

VID usually is PVID from the ingress port


Port based VLANs Ingress filtering rules:

Received frame is untagged

Forward using PVID

Discard

Received frame is tagged

Forward using VID

VID = 0:

» Use only P-bits, forward using PVID

VID = 1

» Default tree, all interfaces

Forward using PVID

Discard


Port based VLANs Egress filtering rules

Interface is in untagged mode

Forward untagged frame

Use configured priorities

Interface is in tagged mode

Set tag based on classification rules

Ingress VID

PVID

P-bits


Ethernet priority 802.1p is amendment in 802.1q

Allow traffic prioritization within Ethernet networks

3 bits -> 8 priorities

Number of queues dependent of HW

At minimum strict priority queuing between queues

Scheduling algorithms are studied in detail later on this course

Mapping traffic to queues is dependent on

Number of queues

Configured policy (egress filtering)‏ MAC address Ethertype DSCP Address


Extending Ethernet Ethernet networks can be extended from LANs to MANs by adding new

mechanisms Larger scale virtualization

More separate virtual networks (4096 ???) Separate forwarding index

Hiding LANs from MANs


Provider networks Provider networks are extensions to customer networks

Provider Bridged Networks extend customer networks with a additional VLANs Provider bridges

Provider Backbone Bridged Networks extend customer networks with additional address structure Provider backbone bridges

Provider Edge Bridge (PEB)

Provider Bridge (PB)

Backbone Edge Bridge (BEB)

Backbone Core Bridge (BCB)

Customer Equipment (CE)

Provider Bridged Network Provider Backbone Bridged Network


Provider network technologies 802.1ad

Q-in-Q

Provider tagging

Enterprise addresses are carried by provider switches service VLANs

Enterprise LANs are aggregated into single provider LAN

802.1ah

M-in-M

Provider encapsulation

Enterprise addresses are invisible for provider switches

Enterprise addresses are aggregated into few provider MACs

ProviderTag#1

ProviderTag#N

EnterpriseHeader

EnterpriseTag

DataProviderQ-Tag

ProviderS-Tag

ProviderHeader

EnterpriseHeader

EnterpriseTag

Data


Q-in-Q Frame Format Provider tagging cascades several Q-tags into the frame

Ethertype 0x88a8

Priority is provider dependent not copied from customer settings

Provider Tag = S-Tag = Service Tag

P-VLAN ID = EVC ID

DataC-DST(6 bytes)‏

(0x88a8)‏(2 bytes)‏

C-VLAN ID(12 bits)‏

C-DST(6 bytes)‏

FCS(4 bytes)‏

P-Priority(3 bits)‏

C-CFI(1 bit)‏

P-VLAN ID(12 bits)‏

(0x8100)‏(2 bytes)‏

P-CFI(1 bit)‏

C-Priority (3 bits)‏


M-in-M Frame Format Provider encapsulation allows second layer of operation

With or without Q-in-Q-tag

With or without Q-tag

First tag in M-in-M header is traffic engineering tunnel tag

Ethernet traffic engineering

Second tag in service tag = I-SID = EVC ID

DataC-VLAN ID(12 bits)‏

C-DST(6 bytes)‏

C-DST(6 bytes)‏

C-FCS(4 bytes)‏

C-CFI(1 bit)‏

(0x8100)‏(2 bytes)‏


P-FCS(4 bytes)‏

P-DST(6 bytes)‏

(0x88a8)‏(2 bytes)‏

P-DST(6 bytes)‏

PQ-Priority(3 bits)‏

PQ-VLAN ID(12 bits)‏

PQ-CFI(1 bit)‏

(0x88e7)‏(2 bytes)‏

Reserved(7 bits)‏

Service ID(24 bits)‏

PT(1 bit)‏


M-in-M Frame Format M-in-M + Q-in-Q allows scalable provisioning of core + metro services

Q-in-Q: Small Metro encapsulation

M-in-M: Large Metro and Core aggregation

Traffic Engineering

State space reduction

DataC-DST(6 bytes)‏

(0x88a8)‏(2 bytes)‏

C-VLAN ID(12 bits)‏

C-DST(6 bytes)‏

C-FCS(4 bytes)‏

P-Priority(3 bits)‏

C-CFI(1 bit)‏

P-VLAN ID(12 bits)‏

(0x8100)‏(2 bytes)‏

P-CFI(1 bit)‏


P-FCS(4 bytes)‏

P-DST(6 bytes)‏

(0x88a8)‏(2 bytes)‏

P-DST(6 bytes)‏

PQ-Priority(3 bits)‏

PQ-VLAN ID(12 bits)‏

PQ-CFI(1 bit)‏

(0x88e7)‏(2 bytes)‏

Reserved(7 bits)‏

Service ID(24 bits)‏

PT(1 bit)‏


Forwarding options What we use as a index in forwarding database

Vanilla case: Destination Address or VID+DA Why to restrict oneself to this

This is just IEEE requirement that one must support legacy Ethernet There will be time, when we must let us free from the burdens of

history Fields that could be used

SA DA VIDs


Forwarding options

MAC based Destination Source and Destination

VLAN based Single Cascaded

MAC and VLAN based Source and VLAN Source + Destination + VLAN Source + Cascaded VLAN Source + Destination + Cascaded VLAN


MAC based forwarding Single FDB where lookup is based on the MAC addresses

Destination MAC Downstream merging

Source and Destination MAC Independent paths


VLAN based forwarding Single FDB where lookup is based on VID values (labels)

Single VID Global values: lookup Link local values: swap

Multiple VID Outer label: forwarding label

Global Link local

Inner label: service label (only visible at the receiver) Multiple FDBs where lookup is based on VID values (labels)

Single VID Partial label space Multicast

Multiple VID Outer label: FDB index (service label) Inner label: Forwarding label


MAC and VLAN based forwarding

Multiple FDBs where lookup is based on MAC addresses VID indexes the FDB

Destination MAC lookup Downstream merging

Source + Destination MAC lookup Independent paths

Single FDB where lookup is based on combination of MAC and VLAN Destination + VLAN lookup

Service dependent downstream merging Source + Destination + VLAN lookup

Independent forwarding paths


Carrier Grade System/hardware/software that is extremely reliable so that it could be used

as a part of a network that is engineered to deliver high availability services Five nines or more

Contains mechanisms to monitor its internal state and to recover from internal error

Contains mechanisms to cope with external influences Fast recovery (conventionally less than 50ms)


Carrier Ethernet Simple idea:

Sell Ethernet services from the carrier infrastructure

Network TechnologySDH/MPLS/IPAccess Technology

Ethernet


Carrier Ethernet Transport Idea:

If access is Ethernet, why not make the core network also with Ethernet

Network TechnologyEthernetAccess Technology

Ethernet


Ethernet vs Carrier Grade Ethernet

Ethernet FDBs are populated by MACs

learning Topology information is flat Loops are solved by RSTP No internal state monitoring Only one virtualization layer (VID)

CGE FDBs are populated statically by

management Topology information is separated

by access and core Loops are handled by routing Internal state is monitored by OAM Multiple layers of virtualization

QinQ MinM Combinations


MetroEthernetForum: Carrier Grade Ethernet

Technology perspective Customer side: semi-transparent Ethernet Provider side: SDH, VPLS, Q-in-Q etc

Service definitions Ethernet line (E-LINE)‏

point-to-point Ethernet LAN (E-LAN)‏

multipoint- to-multipoint Ethernet Tree (E-Tree)

point-to-multipoint


Major changes Service concept

E-LAN, E-Tree and E-Line Connection orientation

Ethernet Virtual Connection (EVC)‏ Filter word for distinguishing packets from different connections

QoS SLA is required for large scale deployment within corporate

interconnections Bandwidth control

Committed information rate control (inherited form FrameRelay)‏


E-Line and E-LAN Services

E-Line Service used to create

Private Line Services

Ethernet Internet Access

Point-to-Point VPNs

E-LAN Service used to create

Multipoint VPNs

Transparent LAN Service

CE

CE

Point-to-Point EVC

MENUNI

UNI

E-Line Service type

CE

CE

CE

MEN

CE

Multipoint-to-Multipoint EVC

UNI

UNI

UNI

UNI

E-LAN Service typeSource: Metro Ethernet Forum


Yes or No. Specifies whether customer VLAN ID is preserved or not.CE-VLAN ID

Preservation

Yes or No. Specifies whether customer VLAN CoS (802.1p) is preserved

or not.

CE-VLAN CoS

Preservation

Service Attribute ParametersService Attribute

Specifies the Frame Delay, Frame Jitter and Frame Loss per EVC or

frames within an EVC identified via their CE-VLAN CoS (802.1p) valueService Performance

Discard or Tunnel per protocolLayer 2 Control

Protocol Processing

Specifies whether broadcast frames are Discarded, Delivered

Unconditionally or Delivered Conditionally

Broadcast Service

Frame Delivery

Specifies whether multicast frames are Discarded, Delivered


Multicast Service

Frame Delivery

Specifies whether unicast frames are Discarded, Delivered


Unicast Service

Frame Delivery

A list of UNIs (identified via the UNI Identifier service attribute) used with

the EVCUNI List

Point-to-Point or Multipoint-to-MultipointEVC Type

Source: Metro Ethernet Forum


None or <CIR, CBS, EIR, EBS>. This Bandwidth profile applies to all frames marked with a particular CoS ID over an EVC.

Ingress Bandwidth Profile Per CoS ID

The maximum number of EVCs allowed per UNIMax. Number of EVCs

Mapping table of customer VLAN IDs to EVCCE-VLAN ID / EVC Map

Yes or No. Defines whether multiple services can be on the UNIService Multiplexing

A string used to identity of a UNI, e.g., NYCBldg12Rm102Slot22Port3UNI Identifier

Discard, Peer or Pass to EVC per protocolLayer 2 Control Protocol Processing

None or <CIR, CBS, EIR, EBS>. This Bandwidth profile applies to all frames over particular EVC.

Ingress Bandwidth Profile Per EVC

Service Attribute ParametersService Attribute

None or <CIR, CBS, EIR, EBS>. This Bandwidth profile applies to all frames across the UNI.

Ingress Bandwidth Profile Per Ingress UNI

No or Yes (all customer VLAN IDs are mapped to an EVC at the UNI).All to One Bundling

No or Yes. Specifies that one or more customer VLAN IDs are mapped to an EVC at the UNI

Bundling

A string used identify an EVC, e.g., NYCBldg1Rm102Slot22Port3EVC3UNI EVC ID

IEEE 802.3-2002MAC Layer

Full Duplex or Auto negotiationMode

10 Mbps, 100 Mbps, 1 Gbps or 10 GbpsSpeed

Standard Ethernet PHYPhysical Medium



Scalability• Services and Bandwidth• 100,000’s‏of‏EVC’s• From Mbps to x10Gbps

Protection• 50ms Protection• End to End Path Protection• Aggregated Line & Node Protection

Hard QoS• Guaranteed end to end SLA• End to End CIR and EIR• Business, Mobile, Residential

TDM Support• Seamless integration of TDM• Circuit Emulation Services• Support existing voice applications

ServiceManagement• Fast service creation• Carrier class OAM capabilities• Customer Network Management (CNM)‏

CarrierEthernet



MEF Vision for NGN

BusinessSubscriber

Service Provider

Transport

IP

IP

• Carries all applications• Internet Access• IP VPN service

• Hard QoS and Traffic Engineering• Better bandwidth utilization/Scalability• Protection Switching (50ms)‏• OAM functions and TDM Support• Any-to-Any VPN services• Multicast support with Hard QoS

ResidentialSubscriber



VPNs in CGE Any-to-any Layer 2 VPN to interconnect multiple locations transparently and

effectively (with high and guaranteed bandwidth)‏

Branch

ISP

IP

Branch

Branch Branch

HQ

Internet

E-LAN



CGE and IP

IP

IP

E-LAN connections among routers Any logical IP topology, multiple EVC’s on a single physical interface

R R

R

R

R

R

R

R

R

R

R

R

IP NetworkUsing Carrier Ethernetas the Transport Layer



CGE and IP IP networks are collapsed in to two layers

Residential customer concentration routers Integrated in DSLAM

Border routers For address propagation and policy control

IP aggregation is vanishing Ethernet aggregation is taking the role of the true transport

Even in 3G networks Look for latest ITU drafts for Ethernet aggregation in 3G networks

Lecture 3: Carrier Ethernet Technology · Ethernet priority 802.1p is amendment in 802.1q Allow...

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